The present invention generally relates to the defrosting of food in bulk, more particularly to equipment and procedures for defrosting boxes or bundles of protein food supplies by subjecting bulk protein food supplies to controlled forced air. The boxes or bundles are formed into stacks having separators to space the boxes or bundles from one another while permitting air flow therebetween. A source of forced air directs defrosting air onto one face of this stack, and a readily collapsible covering supported by the stack defines a defrost tunnel for containing the forced air flow such that same flows between generally horizontal and generally vertical faces of the boxes or bundles of the stack. A plurality of stacks can be included in order to form a train of stacks that defines the tunnel.
In the general context of food processing, it is typically desirable to use fresh protein sources such as meats, poultry and fish. Experience has shown that the quality of protein food supplies is often lessened when the protein food supply is frozen and then must be defrosted prior to processing into a final food product. Nevertheless, it is often advantageous to subject such proteinaceous food products to cryogenic conditions so as to extend the life of the proteinaceous food source in order to preserve valuable food and/or to increase the overall market value of the proteinaceous food supplies by having the ability to hold same in a frozen state until market conditions develop that are more favorable to the meat, poultry or fish processor.
Incorporating a cryogenic holding step in the proteinaceous food product processing procedure adds cost to the procedure due in large measure to needed packaging to reduce the chance of damage during freezing, as well as the energy costs in effecting the freezing and maintaining the frozen products. Additional costs can be encountered in operations that are in the nature of defrosting. In a typical operation, defrosting cannot simply be allowed to occur by unattended standing at a temperature greater than the frozen food. With proteinaceous food supplies, it is important and typically required to closely account for the total length of time that a supply is unfrozen before it enters into the food processing chain. There is thus an important objective to somewhat carefully control the defrosting procedure so that the time of defrost completion can be accurately gauged. Defrosting approaches have been accomplished or proposed which can require specialized and/or expensive equipment and substantial energy consumption. Because of particularly close margins in the proteinaceous food industry, it is important to both minimize equipment and energy costs while at the same time providing a defrosting approach that is nevertheless safe and closely controlled.
Additionally, it is important that any freezing and defrosting approach minimize possible detrimental effects on the quality of the proteinaceous food supply. Many defrosting procedures used heretofore provide protein food supplies that are not of the same quality as fresh protein food sources. These types of protein food sources do not process as satisfactorily as fresh proteinaceous food sources. Often products, for example hams, processed from frozen sources are of reduced quality when compared with those produced from fresh meat. For example, defrosting procedures can retain ice crystals or can defrost in a manner that reduces the quality of the meat such as by increasing purge or by degrading the protein. Improperly defrosted meats can increase the risk of spoilage. In the past, it has been much more acceptable to use frozen protein sources in preparing products that are ground and/or reformed, as opposed to products that are more traditionally of a whole muscle character. For example, heretofore the processing of hams having excellent eating and appearance characteristics has not been consistently achieved when the hog ham portions have been frozen between stun and processing into whole muscle ham products.
In summary, the present invention provides closely controlled defrosting of cryogenically preserved proteinaceous food supplies such as pork, beef, chicken, turkey, lamb and fish. The cryogenically preserved supplies themselves provide a structural component of the defrosting tunnel in accordance with the present invention. Boxes or bundles of frozen proteinaceous food supplies are formed into stacks having spacer racks positioned therebetween in alternating fashion. These stacks, which may be organized into a train of stacks, provide the principal support, structure and shape for the defrosting tunnel in accordance with the present invention. A source of high velocity flow of air at a temperature above that of the proteinaceous food supply directs the air to one face of the stack or train. A readily collapsible air containment device closely surrounds at least the top surface and the right and left vertical faces of the stack or train in order to form a tunnel into which the high velocity air flow is directed. This high velocity air flow proceeds between the boxes or bundles, including passage through the spacer racks therebetween until the air flow exits the tunnel from an open or exit face.
It is accordingly a general object of the present invention to provide an improved forced air defrost tunnel and defrosting process.
Another object of the present invention is to provide an improved forced air defrost tunnel which carries out controlled defrosting.
Another object of this invention is to provide an improved forced air defrost tunnel and process which allows for the use of whole muscle meat that had been frozen prior to completion of processing of same into whole muscle products such as hams.
Another object of the present invention is to provide an improved defrost tunnel and process which is inexpensive and readily broken down for easy storage when not in use.
Another object of the present invention is to provide an improved forced air defrost tunnel for rapidly and uniformly defrosting food processing raw materials without substantial capital costs.
Another object of this invention is to provide an improved forced air defrosting apparatus and method for defrosting ham raw material so as to make smoked cooked hams with quality characteristics equal to hams made from fresh raw materials.